Actually i think he cant even support 50 pep max with hes upload.
The serv itself uses some of the upload. if i where you i would rather go for l2j with your setup than l2off. mainly because your setup for l2off will require a lil more upload than just 512kb/s to run smooth.
Also i hope you got enough cooling on your system as your using an overclocked cpu and you will notice l2off uses alot of your comp not only ram. l2j uses almost nothing at all and can be used on any shitcomp to run ok if ya have enough ram and bandwith.